The feedback-related negativity (FRN) is an electrocortical response observed at the scalp as an apparent negativity approximately 300 ms following feedback indicating monetary loss compared to gain. Our work suggests that the neural differentiation between gains and losses is being driven by a reward-related positive potential that is generated in the ventral striatum-part of the basal ganglia that has been implicated in reward- related neural circuits. In a series of studies, we have found that the FRN is reduced in individuals who are more depressed-and have recently extended this work to middle childhood in pilot studies. This work is consistent with a growing body of data that indicates is characterized by attenuated reward-related brain activity in the ventral striatum. In the current proposal, we extend this work to a large (N=300) sample of 9 year-olds who have been followed as part of a large NIMH-funded study since age 3, to determine whether the FRN is related to depressive symptoms in middle childhood (Aim 1);based on our pilot data, we hypothesize that increasing depressive symptoms in middle childhood will be associated with reduced differentiation between rewards and non-rewards (i.e., a reduced FRN). Moreover, we want to examine whether the FRN is related not only the current depressive symptoms, but to increased risk for MDD in the sample. To address this possibility, the present study will examine the FRN in relation to two well-known risk factors related to the development of MDD: temperamental measures of positive emotionality and familial history of MDD. We predict that children low in temperamental positive emotionality (assessed at age 6) will be characterized by a reduced FRN (Aim 2);further, that children who have a parent who have had MDD will be characterized by a reduced FRN (Aim 3). If Aim 2 and 3 are confirmed, these data would suggest that the FRN may be a risk marker for MDD. The overall goal of this study is to evaluate the relationship between reward-related brain activity and depressive symptoms and risk for MDD in middle childhood. Additionally, the present study will contribute to the literature on the developmental neurobiology of individual differences in temperament and personality. PUBLIC HEALTH RELEVANCE: This study explores the relationship between reward-related brain activity, depressive symptoms, and two of the best-known risk factors for the later development of major depressive disorder (i.e., parental history of MDD and laboratory-based measures of positive emotionality) in a sample of 300 9-year olds. The present study aims to examine whether variation in reward- related brain activity relates to these well-known risk factors for developing depressive disorders;this work could help identify neurobiological markers of risk, and establish diminished neural sensitivity to rewards as an intermediate outcome on the pathway from early risk to the later development of depression.